The SSTL-100 enhanced microsatellite platform expanded the range of SSTL's modular microsatellite to missions of 70 to 130 kg total mass, with a typical payload mass of up to 40 kg.

Whilst building extensively on the MicroSat-70 heritage, the enhanced microsatellite provided substantially greater payload power and volume to match emerging customer requirements. It included orbit station-keeping for constellation applications, and an advanced attitude control system using reaction wheels and control moment gyros for agile and precise pointing. A typical configuration (as used on three Disaster Monitoring Constellation satellites) included 2 Gbytes of on-board storage and dual-redundant 8-Mbit/sec S-band downlinks.

The MicroSat-100 structure was based on the same modular principles as the MicroSat-70. The internal module stack was mounted on larger facets providing accommodation for additional avionics, propulsion and payload subsystems. The volume above the stack was available for payloads, and was generally configured as an Earth-facing aperture.

The MicroSat-100 was proven in orbit by the AlSAT-1 mission, and further units were launched in 2003. The MicroSat-100 provided a proven baseline for customization, or an exceedingly cost-effective off-the-shelf solution for LEO remote sensing missions.